Cover elements (cladding elements) of this type are known especially in magnetic levitation vehicles (DE 10 2004 056 439 A1). The receiving unit having a receiver coil is used for the contactless, inductive transmission of electric power from a track to a vehicle. At least one primary conductor, which is connected to a power source and is designed as a transmitting coil, is provided for this purpose at the track and at least one secondary receiver coil is provided at the vehicle. The receiving unit including the contacting elements belonging to it in the form of plug-type connectors or the like is mounted on a shell-like cover element, which covers a magnetic back box on a side facing the track or is integrated in same. Among other things, carrier magnets for the magnetic levitation vehicle and the means needed for controlling same, which can be operated with the electric power supplied by the receiver coil, are accommodated in the magnetic back box, which is connected via frame straps to an undercarriage or body of the vehicle. An autonomous assembly unit for the “carrying” function is thus obtained.
To improve the magnetic coupling between the primary conductor and the receiver coil and to avoid eddy current losses, the receiver coil is provided with means for concentrating the lines of magnetic flux generated by the primary conductor on its side facing away from the primary conductor. These means contain flux-conducting elements in the form of strips and connection elements connecting the ends thereof, which said connection elements are made of a material with high permeability and high electric resistance, preferably a ferrite, especially a soft ferrite. The strips and connection elements are connected into a grid frame, which is to be placed on the receiver coil, by bonding or according to another method.
The manufacture of flux-conducting elements from a material such as ferrite or the like is carried out by pressing and subsequent sintering of a powder prepared from this material. The flux-conducting elements obtained hereby are comparatively brittle, mechanically delicate and poorly processable. In addition, the joining of the flux-conducting elements into a grid frame is very labor-intensive.
For the same reason, the usual fastening of the receiver coil and of the flux-conducting elements to the cover element by screwing, bonding or the like is not simple. In addition, there is a risk that the flux-conducting elements will be destroyed or become separated because of the mechanical vibrations and shocks occurring during the operation of the magnetic levitation vehicle, which makes undesired maintenance and repair work necessary.